Ridge-furrow planting with plastic film mulching (RM) is widely applied in Northwest China. This study aimed to understand the effects of RM on summer maize growth, yield, water use efficiency (WUE) and soil water dynamics. Two treatments were arranged: ridge-furrow planting with plastic film mulching (RM, crops were planted in the bare furrow with the ridge covered with plastic film) and flat planting without mulching (NM). The Logistic and modified Logistic equations were used to simulate plant height and leaf area index (LAI), and HYDRUS-2D model was used to simulate soil water dynamics after rainfall. The results showed that the maximum growth rates of plant height were 5.1 and 5.2 cm/d on the 39th and 41th day after sowing, under RM and NM respectively. The maximum growth rate of LAI under RM was 14.6% higher and occurred 2 days earlier than that of NM. The ear length, kernel number per ear, 100-kernel weight, yield and WUE of RM were 7.8%, 15.4%, 1.3%, 6.0% and 3.1% higher than those of NM, respectively. The simulated results of HYDRUS-2D model showed that RM increased the average soil water content in 0—200 cm profile, especially in 0—20 cm layer after rainfall. Finally, it could be concluded that RM could increase yield and conserve water when comparing with NM, however, the effect on increasing yield is depend on the meteorological condition of summer maize growth stage, if the weather is too wet or too dry, RM may has little profit on yield.